oldfiles_spec: Add tests for ":filter ... oldfiles"

test/functional/ex_cmds/oldfiles_spec.lua

@@ -4,6 +4,7 @@ local helpers = require('test.functional.helpers')(after_each)
 local buf, eq, feed_command = helpers.curbufmeths, helpers.eq, helpers.feed_command
 local feed, nvim_prog, wait = helpers.feed, helpers.nvim_prog, helpers.wait
 local ok, set_session, spawn = helpers.ok, helpers.set_session, helpers.spawn
+local eval = helpers.eval
 
 local shada_file = 'Xtest.shada'
 
@@ -42,6 +43,38 @@ describe(':oldfiles', function()
       Press ENTER or type command to continue^                                                             |
     ]])
   end)
+
+  it('can be filtered with :filter', function()
+    feed_command('edit file_one.txt')
+    local file1 = buf.get_name()
+    feed_command('edit file_two.txt')
+    local file2 = buf.get_name()
+    feed_command('edit another.txt')
+    local another = buf.get_name()
+    feed_command('wshada')
+    feed_command('rshada!')
+
+    local function get_oldfiles(cmd)
+      local t = eval([[split(execute(']]..cmd..[['), "\n")]])
+      for i, _ in ipairs(t) do
+        t[i] = t[i]:gsub('^%d+:%s+', '')
+      end
+      table.sort(t)
+      return t
+    end
+
+    local oldfiles = get_oldfiles('oldfiles')
+    eq({another, file1, file2}, oldfiles)
+
+    oldfiles = get_oldfiles('filter file_ oldfiles')
+    eq({file1, file2}, oldfiles)
+
+    oldfiles = get_oldfiles('filter /another/ oldfiles')
+    eq({another}, oldfiles)
+
+    oldfiles = get_oldfiles('filter! file_ oldfiles')
+    eq({another}, oldfiles)
+  end)
 end)
 
 describe(':browse oldfiles', function()